Using arrays inside a list in C#

Since you have to have a log title and entry, have you considered wrapping those in a separate class rather than using an array of two strings?

I mean doing something like this:

public class LogItem
{
    public string Item;
    public string Entry;
}

Then instead of having a list of arrays, you would just use a list of LogItem:

var myList = new List<LogItem>();

var myNewLogEntry = new LogItem {Title = "Entry title", Entry = "Entry message"};

myList.Add(myNewLogEntry);

You can easily make list of arrays:

var myList = new List<string[]>();

myList.Add(new [] { "Fruit", "Orange" });
myList.Add(new [] { "Car", "Toyota" });

Console.WriteLine(myList[0][1]); // Prints "Orange"
Console.WriteLine(myList[1][0]); // Prints "Car"

Note, that array length for the particular item may differ. There's no way to limit it.

I'm not sure if this goes against the assignment, but I would suggest thinking a bit object oriented about this, consider what you're asking for:

We are supposed to do is put log entries (title and entry) in a sort of journal.

In my head this translates to two classes:

First a class "Log" with two string properties, "Title" and "Entry" Second a class "Journal" with a List<Log> property named Entries.

Code example:

public class Journal
{
    ...
    public List<Log> Entries { get; set; }
}

public class Log
{
    public string Title { get; set; }
    public string Entry { get; set; }
}

You can simply create it like that. Is that what you were looking for?

List<string[]> myList = new List<string[]>();

This is a completely valid data structure.

List<string[]> logList = new List<string[]>(); 
logList.Add(new string[] {"item 1", "item 2", "item 3"});

Besides this, I am not sure what you are looking for.